Pressure boosting cylinder



July 21,. 1942. N. A. CHRISTENSEN PRESSURE BOOSTING CYLINDER Filed Sept.6, 19 39 2 Sheets-Sheet l INVENTOR'.

|I J l 'i I m Nc'elfi BY w Wm ATTORNEY.

a N. A. CHRISTENSEN 2,290,537 PRESSURE BOOSTING CYLINDER INVENTOR;

2 Sheets-Sheet 2 Filed Sept. 6, 1959 Nielbflflw BY I ORNEY.

Patented July 21, 1942 UNITED; STATES PATENT; OFFICE g I 2,290,537 a aPR-EssUR BoosTING CYLINDER.

Niels}. Christensen, Cleveland, Ohio Application September 6,1939,Serial No. 293,549 2 Claims. (01. fill-54.6) I

This invention relates to a pressure boostingmeans or valve forhydraulic systems foraircraft and the like and while adaptable to anyhydraulic brake system, it'is particularly applicable to aircraftandother systems where the fluid pressure is to be raised and heldconstant. Therefore, the principal object of the present in.- vention isthe*provision of an improved pressure raising means capable of receivingfluid at a lower pressure than that desired for use .on brake cylindersand maintaining the pressure in the brake cylinder constant.

In certain types of airplanes the braking units require pressure fromfour hundred pounds per square inch upward and the pressure is derivedfrom a low pressure-source which may be eitherv compressed air, vacuumor liquid such, for instance, as oil taken from the engine lubricatingforce feed system which usually has a pressure of from'forty to sixtypounds per square inch and it, therefore; becomes necessary to stepupthispressure for brake use. object of the present invention is theprovision of a light weight boosting means, simple and inexpensive inconstruction and positive and efficient in operation. 1

In the drawings accompanying and forming a part of thisspecificatiomFig. l is a longitudinal sectional view of this improved.boosting means, and i Fig. 2 is a similar view of a slightly modifiedform adapted for use with vacuum pressure.

denoted by 4. At one end of this cylinder 4, as the inlet end, thecasing'2 is closed, by a part thereof as and is provided with an inletopening viiwhich may be threaded or otherwise provided with means forattachment to the line leading from the pressure control valve. Theother end of the cylinder 4 is closed by means of an enlarged head 1 ofan interior stationary piston 8 and'is secured to the casing]. bysuitable means such as the bolts 9. a

The interior of the piston 8 has a bored passage or chamber II open atits inner end and in communication .atits outer end with a threadedoutlet opening l2 adapted to bevsecured to the line leading tov thebrake cylinder. The exterior portion of .the piston is provided withoutwardly extending flanges I3 and i4 for reception of suit- Hence, afurther Similar characters of reference indicate corresponding parts inthe several views.

Before explaining in detail the present improvement and mode ofoperation thereof, I desire to have it understood that the invention isnot limited to the details of construction and arrangement of partsillustrated in the accompanying drawings since the invention is capableof other embodiments, and that the phraseology employed is for thepurpose of description and not of limitation.

This booster mechanism is placed between the brake cylinder and ametering control valve as is usual either in reducing or boostingmechanisms and reference is made to Fig, 6 of my application forpressure reducing means filed herewith for an illustration of this valvein the brake system.

Fig. 1 illustrates 'one form of this device for use with either liquidor compressed air and comprises a main casing or housing 2 within whichand adjacent to the inner wall a shell or sleeve 3 is closely flttedandthe casing 2, together with the sleeve 3 form the outer cylindergenerally able packing rings i5 and these extensions form the annularchambers l6 and I1.

Slidably located within the cylinder 4 is a pis ton I8 having a sleeve[9 forming the cylinder 20 which is the high pressure chamber betweenthe piston and outlet i2.' This cylinder 20 fits and slides over. thepiston 8 a'ndthe'packirig rings l5 make a tight fit preventing leakageof fluid. The piston i8 is provided with an outwardly extending flange22 adapted to slideflalong the inner wall of the cylinder 4. Thisflange, together with the head of the piston It forms the annularchamber 23. The projection 22 and the head of the piston it are providedwith suitable'packing --rings 24 to make a tight flt with the wall ofthe cylinder. 4,- A spring 2| is located between the enlarged end I ofthe piston 8 and the projection 35 22 of the piston l8. Between the headof the piston l8 and inlet 6, a working pressure fluid chamber In isprovided within the cylinder 4. This in case of Fig. 1 would be lowpressure compressed air or low pressure liquid butyin case of Fig. 2 itwill be air at atmospheric pressure through breather 29 when a partialvacuum has been created bysuction through the connection 28.

The sleeve portion IQ of the piston l8 forming the cylinder 20 is ofsuitable size to permit it readily to slide over the outwardly extendingflanges l3 and I4 of the stationary piston 8, and this sleeve portion 19is provided with laterally extending ports 25 located between the flange22 and the head of the piston l8 and communicating with the cylinder 20and chamber 23 when the ports are open as when the piston is in' brakerelease position as illustrated. The cylinder 4 is provided with a port26 opening into:

the chamber 23 at one end and to a'threaded passage 21 in the casing 2to which is secured a fluid reserve tank H having an air vent H. An airvent 28 is provided in the end of the cylinder connecting the chamber iiof the cylinder to the atmosphere.

The operation of the device is as follows:

With the brakes in released position, the parts are in the positiorillustrated inthe-drawings and fluidfro'm the reserve-tank H ispermitted to flow through the port 26 in the chamber 23 and through theports 25 into the cylinder 10 ,1 of the piston l8 thereby keeping thebrake line 1 "invention and described a way of constructing The operatorby means of the control. valve passes low pressure fluid either airfroman air tank or oil from the engine lubricating force" feed systemii'zsiso that the cylinder! isno longer scc and entrapping fluid in thecylinder 20. Com: piston it causes the piston the outlet forcing fluid'ure boosted in proportion;

tinued pressure'on the to, shift further towe, to the brakes irra pre piessuremay be held contor'since the piston remains ant by in balance. inaccordance withrpressure. exerted from the controlval've to the pressureonthe brakes. Wheiilthe'operator releases the pressure ports 25 are.soposlelo'f the piston, they piston Y 1 In; thegniodifidiorm ar thesarne and, .therefore, have been given the same referencenumerals, the only"changes being that the -.air: vent L llie: attached to the casing Hitself andxis provided with. suitable means forattachmentfifiaxyacuumgline andinthis' form, 45

a suitable; breather screen 293s attached-tothe inletii connecting theinlet-with'atmosphere.

The operation is the same except that vacuum 1 through the inlet 5,causing the pistonto shiittoward the outlet end closing etreldf'llo 1reservoir chamber 23- 2o er Hi to the'a-rea. of the 25 I aclrin' h ing15 of the d iofthesa onay. v hown in Fig. 2, he parts 40 or suction isexerted through the vent 28 to exhaust the air in the chamber i6 and theair pressure on the end of the piston 18 through the inlet 6 beinggreater than that in the chamber l6,

5 causes movement of the piston toward the outlet to eilect a boostingof pressure on the brakes, as hereinbefore explained in connection withFig. 1. .It is-to be understood that, by describing in detail v hereinany particular form, structure or arrangement, it is not intended tolimit the invention beyond the terms of the several claims.

Having thus explained the nature of my said andu sing the same, althoughwithout attempting to: set fortlra-ll of the forms in which it may bemade orall oi the modes of its use, 1 claim: 1 A self-contained pressureboosting means,

comprising a cylinder having an inlet and outlet, I

a hollow lowvpressurepistonhaving a pair of spaced-flanges sliding onthe walls of said cylinder and defining a-shifting reservoir chamberbetween-the cylinder and piston, said piston sepa rating the inlet fromthe outlet and having ports betweensaid reservoir and the interior ofsaid piston, the interior of. said piston forming a high pressurechamber, anda high. pressure piston v operating in the interior of saidlow pressure piston to close saldports when the low pressure piston vismoved by pressure fluid entering the inlet and to open said ports whenthe low pressure piston returns'to normal position to replenish thefluid supply in said high pressure chamber.

= 2; A self-contained pressure boosting means comprising a cylinderhaving an inlet and outlet in opposite ends thereof, a hollowpr'lmary'piston shiftable in said cylinder and having a pair of spacedflanges, provided-with packing rings sliding on they walls. of. saidcylinder to space the piston therefrom and to. define a low air pressurechamber on oneside of one .of said flanges and an annular liquid chamberon the other side of f said flange,- a cylinder in said piston forming ahigh pressure liquid chamben and a secondary hollow piston connectingwith the high pressure outlet and having a pair of spaced flangesprovided with packing rings sliding on the walls of said cylinder in theflrst named piston.

' NIELS A. CHRISTENSEN.

